Aryl sulfonate stabilized cobalt carbonyl complex compounds

ABSTRACT

The destructive dissociation of a cobalt carbonyl complex compound in the liquid phase is inhibited by the presence of an aryl sulfonate stabilizer.

United States Patent Wilkes Dec. 23, 1975 ARYL SULFONATE STABILIZED COBALT CARBONYL COMPLEX COMPOUNDS [56] References Cited [75] Inventor: John B. Wilkes, Richmond, Calif. UNITED STATES PATENTS [73] Assignee: Chevron Research Company, San 3,733,361 5/1973 Deffner et a1 252/428 Prams, Callf- FOREIGN PATENTS OR APPLICATIONS Filed: 1, 1974 530,889 9/1956 Canada 260/604 [2]] Appl. No.: 447,173

Primary Examiner-Patrick P. Garvin Related Apphcauon Dam Attorney, Agent, or Firm-G. F. Magdeburger; John [60] Continuation-impart of Ser. No. 300,053, Oct. 24, Stoner J T, G, DeJonghe 1972, abandoned, which is a division of Ser. No. 32,386, April 27, 1970, abandoned.

[57] ABSTRACT 260/604 The destructive dissociation of a cobalt carbonyl com- 260/632 HF plex compound in the liquid phase is inhibited by the Int. GL2 presence of an sulfonate stabilize1' [58] Field of Search 260/604 HF, 632 HF; a

252 23 443 5 Clauns, No Drawings ARYL 'suLFoNATEs'TAinLIzEu COBALT. CARBONYLCOMPLEX COMPOUNDS,

CROSS-REFERENCE TO RELATED APPLICATIONS I FIELD OF INVENTION This invention relatesto a method for the stabilization of acobalt' carbonyl complex compound in the liquid phase. More particularly, it relates to a method for the stabilization of cobalt carbonyl complex c,om-. pounds in a hydr'oformylation reaction system effected by the action 'of an aryl sulfonate inhibitor. Still more particularly, this invention relates to the use of alkyl aryl sulfonate compounds as catalyst stabilizers in,the production of alcohols and/or aldehydes from olefinically unsaturatedorganic compounds by the cobalt carbonyl catalyzed addition reaction of carbon monoxide and hydrogen to the carbon-to-carbon linkage(s) of these unsaturated compounds.

. BACKGROUND OF INVENTION Cobalt carbonyl compounds including dicobalt i ctacarbonyl," cobalt hydrocarbonyl, et'cfjas suchor' in modified forms'are' known for their use as catalystsforj a variety of reactions relating to olef nic unsaturated organicbompounds including the hydroformylation (oxonation) of olefins, isomerization of olefin's, carbonylation of amines and aromatic nitriles, hydrosilation of 'olefins and the, like. These "catalyst complexes are subject to serious limitations in that unless carbon 'mon-' oxide'pres'sures excess. of cobalt carbonyl complex equilibrium valuesaremaintained in their presence, a1

destructive dissociation intocobalt metal and residue occurs under'reactio'n conditions. Catalytic activity is thus lost and cobalt metal is plated out on reac-tor'walls and associated-transfer piping. From time to time t'he similar-undesirably corrosive and inconvenient agent.

' THE INVENTION It has now been found thataryl sulfonate solutes I inhibit the destructive dissociation of cobalt carbonyl system in contact with the contained solution. In addition, the presence of at least-a minoramount,"e.g.,'-

0.001 mol per mol of cobalt in the complex compound of an alkyl aryl sulfonate in a hydroformylation reaction mixture stabilizes th e cobalt carbonyl complex compound comprising'the hydroformylation catalyst 1 by inhibiting the destructive dissociation ordinarily".

experienced'by these catalysts in the hydroformylation, of unsaturated organic compounds under hydroformy lation reaction conditions. Aryl sulfonates of the for-- an integerxiri the 'rangefrom l to about 4, inclusive, and in which the R groups where-n is greaterthan 1 may be the. same-or different, areusefulfor the stabilization of cobaltwcarbonyl complexcompounds in the hydroformylation of unsaturated organic compounds.

f In addition to the aforedescribed advantages which obtain from the use of an aryl sulfonate in conjunction with a cobalt carbonyl complex compound'in the liquid phase, surprisingly, the presence of these inhibitors permits. the employment of carbon monoxide pressures well below conventional-equilibrium pressures for cobaltcarbonyl-complex compounds in hyd'r'oformylationj:

reaction-systems where the sulfonate is' the sol'e'rion gaseousvst'abilizer present.

ratio of 1:0.0015:0.000l5, respectively. Hydrogen and carbon monoxide gas are charged to the sealed autoclave in the mol-ratio2:l, respectively, and the reactor 1 andcharge is maintained at a temperature of about 175-180C. and a total system pressure of about 1800-2000 'psigfor a period of about 2 hours. The resulting product mixture contains, based upon the olefin feed, about -95 weight percent of nonyl alcohol, a trace of nonyl aldehyde, about 8-9 weight per cent of alkane and about 25 weight percent ofhi'gh molecular weight 'byaproduct (called thick oil in the oxonationart). Little or no coba'ltmetal isfound to be: deposited upon the walls-of the reactor an'd most-ofthe' cobalt.- charged, is present in the productmixture *as' The hydroformylation of unsaturated organic com pounds catalyzed by cobalt carbonyl complex" compounds using carbon monoxide and hydrogen (i;e., the classic unmodified oxo-reaction system) iswellknowri in the art. The additionof the aryl' sulfonates of the present invention to the unmodified hydroformylatio'n reaction systems of this prior art -is..in general beneficial and is contemplated herein including the reaction conditions, catalysts and reactants. i I

Brifi ly, hydroformylationJreactions'may be illus trated by the general equation:

wherein the unsatisfied valence bonds are attachments to the atoms or radicals necessary to complete the olefinic'compound. Substantial'partial pressures of carbon monoxide and hydrogen are required for the reaction to proceed with-suitable relative proportions of hydrogen'to carbon monoxide being in the range 0.5-10to 1 respectively, and preferably 1-3 to '1. Nor

mally in the absence of a suitable catalyst stabilization mula R YSO M inlwhich R: is an unsubstituted alkyl group having acarbon atom content in the range from about 3 to 30;inwhich ;Y is an aryl aromatic carbocyclic nucleus havinga carbon atom content inthe range- 65 corresponding temperatures being in the range to from 6 to about13, in which M isa cation of the group ammonium, calcium and the alkalimetals, in which n is means,.satisfactory total pressures (carbon monoxide plus hydrogen) are in the range .700 to 10,000 psig with 250C. The present aryl. sulfonate stabilizers permit satisfacto'ry1operation at'systern pressures in'the'range from about 50 psig to up to about 4000-5000 psig with the corresponding temperatures beingabout 75to 225C preferably 125 to 200C; 1

By a hydroformylation,-reactor, as used herein, is

meant a pressure reactor, autoclave and the like, as known in theart.

In the absence of a suitable stabilization means'cobalt carbonylcomplex compounds equilibrate into a system which contains many members, including dicobalt octacarbonyl, cobalt hydrocarbonyl, the salt Co[Co(- C) etc. Any and all of these complex compounds are either useful hydroformylation catalysts per "se or are catalyst precursors. Cobalt metal may also be a member of the above noted equilibrium'set. However, in hydroformylation reactions for all practical purposes the formation of cobalt metal is an irreversible reaction and one to be avoided. Usually it is more convenient to prepare the catalyst in situ by the reaction of a cobalt oxide, a cobalt salt or soap with hydrogen and carbon monoxide in the vesselcontemplated for use in a hydroformylation reaction. I

The medium for the in situpreparation in general comprises a liquid reactant, for example an unsaturated organic compound or an olefinic hydrocarbon, from a reaction system for which the cobalt carbonyl complex is to serve as a catalyst. Inert liquid media or diluents such as saturated hydrocarbons, aromatic hydrocarbons, alcohols, high-boiling reaction byproducts,-etc.,

as knownin the art, may also be employed.

The organic liquid medium is substantially free of water, and the aryl sulfonates used herein are not used to reduce. surface tension'of water. Thus the organic medium is an essentially anhydrous organic liquid medium; the examples hereinbelow illustrate suitable anhydrous liquid organic media for'the present invention.

In general, best results in terms of stabilization effects obtain when the stabilizers of the present invention are present initially, although good results are also experienced from a subsequent addition. Preferably one or more of the subject compounds are the sole stabilization means other than carbon monoxide in the reaction system.

In the active form, the stabilized cobalt carbonyl catalyst will contain most of the cobalt component in a reduced valence state, usually zero or possibly even a l valence.

As used herein, the term complex compound" relates to combinations of two ormore atoms, ions, or'

molecules which arise as a result of the formation of a bond(s) by the sharing of a pair(s) of electrons originally associated with only one of the components, and

the complex possesses identifiable physical or chemical characteristics of a distinct species.

Aryl sulfonate solutes in general appear to be beneficial in the stabilization of cobalt carbonyl complex compounds where the cation is ammonium, an organic nitrogen base, an alkali metal, alkaline earth metal, or mixtures thereof. Aryl sulfonates of the formula R Y- SO M, and molecular mixtures thereof, as defined above, are preferred for use herein, in particular where n is l and the carbon atom content of the alkyl hydrocarbon radical portion of the sulfonate is in the range from about 12 to 30, where Y is a benzene nucleus and where M is an alkali metal cation. Representative satisfactory carbocyclic nuclei for the above formula include benzene, naphthalene,biphenyl and the like aromatic rings. Benzene and naphthalene sulfonates are preferred. I

Satisfactory alkyl radicals, R, for the above formula have a carbon atom content in the range from 3 to about 30 and representative radicals include s-octyl, n-octyl, t-butyl, i-propyl, n-propyl, s-tetracontyl, s-(2- methyl)-octyl, t-(3-ethyl)-nonyl, s-dodecyl, s-eicosanyl, s-nonadecanyl, n-hexyl, s-heptyl, s-decyl, t-(3- methyl)-tetradecyl, s-octacosanyl, s-triacontanyl, nnonacosanyl, and the like alkyl hydrocarbon radicals. Straight chain alkyl hydrocarbon radicals are preferred.

Representative cations, M, for the above formula include lithium, sodium, potassium, calcium, and nitrogen containing ions of the formula R N wherein the groups R are the same or different and may be hydrogen, or an alkyl hydrocarbon radical having a carbon atom content in the range from I to about 20, such as ammonium, C H NH (CH N C H CH NH the like cations. Sodium is preferred. Representative inhibitors/stabilizers useful in the invention include the sodium, ammonium, lithium and calcium salts of the aryl sulfonic acids s-hexadecyl benzenesulfonic, di-soctyl benzenesulfonic, tri-isopropyl naphthalenesulfonic, 4-s-octadecyl biphenylsulfonic, n-decyl benzenesulfonic, s-octyl, s-dodecyl benzenesulfonic, s-eicosanyl benzenesulfonic, tri-s-octyl benzenesulfonic, snonadecyl naphthalenesulfonic, s-octyl, s-dodecyl naphthalene sulfonic, s-hexadecyl, s-pentadecyl ben-,;

zenesulfonic, s-butyl, s-tetradecyl benzenesulfonic, and the like acids.

The relative amount of the stabilizer which should bev employed varies, depending upon the particular reaction conditions being employed. At the lowerreaction of the larger relative amount. Usually better results 1 obtain when the ratio is substantially less than stoichiometric, i.e., in the range from about 0.1-0.25 to 1, respectively.

The amount of catalyst desirably employed in the present process corresponds to prior art requirements. Usually catalyst concentrations, based upon the olefinically unsaturated feed (weight percentages) and calculated as cobalt metal in the range 0.05 to 5.0 weight percent are satisfactory. Preferred amounts arch the range 0.1 to 0.5.

Olefmically unsaturated organic compounds as known in the hydroformylation (oxo) art are, in general, satisfactory feeds for use in the present invention. Preferred feeds are monoolefinic hydrocarbons. Of these, linear olefms of the C to C range, propylene oligomers and the like, are the most desirable feeds. Where branched chain olefins are used for the production of oxo-alcohols, it is often more advantageous to effect the carbon monoxide-hydrogen addition to the Representative olefinic hydrocarbons suitable for use herein include ethene, propene, l-hexene, cyclohexene, beta-pinene, alpha-pinene, Z-heptene, 3-ethylpentene-l, 2-methylpentene-2, cyclopentene, di-isobutylene, propylene trimer, co-dimer heptenes, vinylcyclohexene, cyclododecene, 3-eicosene, l-dodecene and the like olefinic hydrocarbons.

COBALT CARBONYL STABILITY TEST The stabilizing action of the inhibitors of the present invention upon complex cobalt carbonyl compounds is shown by means of a suitable test. The relative stabilizing action is shown by comparative examples subjecting them to a standard set of conditions with and without the added aryl sulfonate. These conditions include:

Temperature, C. 190

absence of stabilizers and under the foregoing conditions all of the cobalt carbonyl is converted to a cobalt metal plate which is found adhering to the walls of the glass liner and autoclave. In the presence of an effective stabilizer, little or no metal plating-out occurs, or but small amounts of filterable metal powder are formed. With stabilizers of intermediate effectiveness, little or no metal is found in the liner; but metal is found outside the liner, either deposited on the external liner wall or the autoclave wall, or loosely lodged between the liner and the autoclave wall. Decompositions outside the liner appear to be due to the higher temperatures which exist at the autoclave wall because of the proximity of the heating element and the low level of the stabilizer. The stabilizer inhibits decomposition of the cobalt carbonyl in the solution inside the liner, but does not prevent some diffusion through the vent holes in the liner into the void between the liner and the Time 6 autoclave inner wall. In Table I below is listed a number Solvent Mixed alcohol-alkane" f HZICO mo ram 21 o representative test results.

TABLE I ARYL SULFONATE STABILIZERS FOR I-IYDROFORMYLATION SYSTEMS Stabilizer Cobalt as z( )a, Wt.% 00" Moles Per Pressure of No. Type Solution Mole Co. Psig Cobalt Fed Observations 1 None 1650 0 Metal plate on liner walls.

2 Pyridine 0.16 0.50 1700 0 Metal plate on liner I walls.

3 RC I-I SO Na 0.12 1750-1850 71 Clean, no metal plate.

4 (R'Rcnnsomca 0.09 64, 38 Some metal plate on 38% run.

5 R C H SO Na 0.12 61 Clean, no metal plate.

8 RC I-LSO Na 0.12 ll Some metalplate noted metal dispersion.

""All runs with 0.236 grams of cobalt as octanoate in g n-heptane 50 g C -C oxo alcohol.

"Zzl, H zCO "R is C -C linear alkyl "'R is C -C linear alkyl R is G -C linear alkyl 'R is C linear alkyl 'R is C C. branched alkyl R'is c,,-c,n linear alkyl R is C linear alkyl "R is C C polypropyl alkyl Pressure, psig 1600-1800 "All runs with 0.236 grams of cobalt as octanoate in 50 g n heptane and 50 g C,,C, oxo alcohol.

The above comparative examples illustrate that alkyl aryl sulfonates are effective stabilizers for cobalt carbonyl complex compounds. In similar tests where the cation is Li, N-H K, C I-I CH NH5, andthe like, similar stabilization effects are notable.

EXAMPLES l0 1 3 Advantages of the instant stabilization method are illustrated by comparative examples in which a representative feed, l-octene, is converted to oxo alcohols in a cobalt carbonyl catalyst hydroformylation using commercial catalyst requirements, e.g., 0.2-0.5 weight percent of cobalt based upon olefin and other conditions,

as noted in Table II below.

TABLE II HYDROFORMYLATIONS WITH ARYL SULFONATE ADDITIVES Cobalt Additive Solvent Olefin Moles Wt. Per

of Mole No. Source Olefin Type Grams Co Type g Type Grams l Co-octanoate 0.25 di-linear" 0.12 0.10 None l-octene 75 C -C alkylbenzene Na sulfonate l l Co-octanoate 0.25 linear 1.3 1.0 None l-octene 75 C\ C18 alkyl benzene Na sulfonate 12 Co-octanoate 0.25 tri-isopropyl- 0.1 0.12 None l-octene 75 naphthalene-Nasulfonate (a) 13 pre-activated 0.19 tri-isopropyl- 0.05 0.08 n- 50 l-octene 50 co-octanoate napht alene-Naheptane sulfonate Reacgon Conditions Products Wt. of Olefin :C Temp Mole Press Time, Alde- Hydro- Thick C. Ratio Psig Min. Alcohol hyde carbons Oil 165 1.221 1300 60 195 3:1 1800 60 100 Trace 2.6 177 2:1 1900 120 91 Trace 8.8 25 177 2:1 1900 90 48 7 l8 177 2:1 I800 60 52 22 9% (a)Catalyst pie-activated by reacting 90 min. at 190C, 2:1 H,:C0, 1800 psig, in solvent without olefin: cool to 65C.. add olefin.

(Runs I2, 13 gave apparent low yield due to acetal formation. Needed more time, or higher temp.)

in the above hydroformylation examples the walls of the reactor were visually checked for the presence of a cobalt metal plate. None was notable.

These examples illustrate that alkyl substituted aryl sulfonates are effective stabilizers for cobalt carbonyl complex compounds under hydroformylation reaction conditions.

EXAMPLES l4-l5 The following examples illustrate the hydroformylation of a l-alkene feed, a C -C alpha-olefin mixture, under conventional unmodified conditions using 0.20.5 weight percent of cobalt based upon the olefin and the balance of the conditions and with the results as in Table III below.

From a comparison of Examples 14 and 15 with Examples 9-13, it is evident that alkyl aryl sulfonates stabilize complex cobalt carbonyl compounds, thereby permitting the use of lower system pressures in the hydroformylation of hydroformylatable' unsaturated organic compounds.

It will be readily appreciated from the foregoing disclosure and examples that variations can be made by those skilled in the art without departing from the scope and spirit of the appended claims.

I claim:

1. The method of inhibiting the'formation of a cobalt metal plate on the surface of a system containing a cobalt carbonyl complex compound in a substantially water-free organic liquid medium and in the presence of carbon monoxide, said inhibition being in connection with the surface in contact with the organic liquid medium, which comprises adding an alkyl aryl sulfonate solute to the organic liquid medium, and wherein said alkyl aryl sulfonate is of the formula R YSO M, wherein Y is an aryl carbocyclic nucleus having a carbon atom content in the range from 6 to about 13, wherein R is an alkyl hydrocarbon group having a carbon atom content in the range from about 3 to 30, wherein M is selected from the group consisting of alkali metal, calcium and ammonium cations, said ammonium ions being of the formula R 'N wherein the groups R are the same or different and may be hydro- 5 gen or alkyl hydrocarbon radicals having a carbon atom content in the range from about 1 to 20, and wherein n is an integer in the range from 1 to 4, inclusive, and where n is greater than 1, said R may be the same or different groups, and wherein for each mol of cobalt carbonyl complex in the organic liquid medium there is present 0.001 to 2 mols of alkyl aryl sulfonate.

2. A method in accordance with claim 1 further characterized in that the stabilizer is a sodium monoalkyl benzene sulfonate in which the alkyl group has a carbon atom content in the range from about 12 to 30.

3. A method in accordance with claim 2 further characterized in that said alkyl group of the sulfonate is a straight-chain radical.

9 10 4. A method in accordance with claim 1 further char- 5. A method in accordance with claim 1 further charr i d th t f h l f b lt i h reaction acterized in that for each mol of cobalt in the reaction mixture an amount of the aryl Sulfonate in the range mlxture an amount of the aryl sulfonate 1n the range from about 0.1 to 0.25 mol is present in the mixture.

from about 0.001 to 0.5 mol is present in the mixture. 5 

1. THE METHOD OF INHIBITING THE FORMATION OF A COBALT METAL PLATE ON THE SURFACE OF A SYSTEM CONTAINING A COABLT CARBONYL COMPLEX COMPOUND IN A SUBSTANTIALLY WATER-FREE ORGANIC LIQUID MEDIUM AND IN THE PRESENCE OF CARBON MONOXIDE, SAID INHIBITION BEING IN CONNECTION WITH THE SURFACE IN CONTACT WITH THE ORGANIC LIQUID MEDIUM, WHICH COMPRISES ADDING AN ALKYL ARYL SULFONATE SOLUTE TO THE ORGANIC LIQUID MEDIUM, AND WHEREIN SAID ALKYL ARYL SULFONATE IS OF THE FORMULA RNYSO3M, WHEREIN Y IS AN ARYL CARBOCYCLIC NUCLEUS HAVING A CARBON ATOM CONTENT IN THE RANGE FROM 6 TO ABOUT 13, WHEREIN R IS AN ALKYL HYDROCARBON GROUP HAVING A CARBON ATOMS CONTENT IN THE RANGE FROM ABOUT 3 TO 30, WHEREIN M IS SELECTED FROM THE GROUP CONSISTING OF ALKALI METAL, CALCIUM AND AMMONIUM CATIONS, SAID AMMONIUM IONS BEING OF THE FORMULA R4''N(+) WHEREIN THE GROUPS R'' ARE THE SAME OR DIFFERENT AND MAY BE HYDROGEN OR ALKYL HYDROCARBON RADICALS HAVING A CARBON ATOMS CONTENT IN THE RANGE FROM ABOUT 1 TO 20, AND WHEREIN N IS AN INTEGER IN THE RANGE FROM 1 TO 4, INCLUSIVE, AND WHERE N IS GREATER THAN 1, SAID R MAY BE THE SAME OR DIFFERENT GROUPS, AND WHEREIN FR EACH MOL OF COBALT CARBONYL COMPLEX IN THE ORGANIC LIQUID MEDIUM THERE IS PRESENT 0.001 TO 2 MOLS OF ALKYL ARYL SULFONATE.
 2. A method in accordance with claim 1 further characterized in that the stabilizer is a sodium monoalkyl benzene sulfonate in which the alkyl group has a carbon atom content in the range from about 12 to
 30. 3. A method in accordance with claim 2 further characterized in that said alkyl group of the sulfonate is a straight-chain radical.
 4. A method in accordance with claim 1 further characterized in that for each mol of cobalt in the reaction mixture an amount of the aryl sulfonate in the range from about 0.001 to 0.5 mol is present in the mixture.
 5. A method in accordance with claim 1 further characterized in that for each mol of cobalt in the reaction mixture an amount of the aryl sulfonate in the range from about 0.1 to 0.25 mol is present in the mixture. 